A conventional art relating to the three-dimensional image measuring apparatus is disclosed in U.S. Pat. No. 4,794,550 (filed on Oct. 15, 1986, applicant: Eastman Kodak Company), which will be described hereinafter in accordance with an accompanying drawing.
FIG. 1 is a construction view of the three-dimensional image measuring apparatus in accordance with a conventional art. As shown in FIG. 1, light generated from a light source 1 is irradiated as horizontal light beam 1a having a period “d” of the grating image onto a surface 9 of the measuring object through a grating 2, which is moved toward “a” direction of an arrow by a grating transfer member 4, and a lens 3. The irradiated light is scattered by angle 1b and irradiated to a camera 7 having an image sensor 6 through a lens 5 and then a sample image is obtained. The obtained sample image is processed by a computer 8 and then a three dimensional image of the surface 3 of the measuring object is obtained and then the obtained three dimensional image is displayed by a display device 8b. Here, a keyboard 8a is used for inputting several information in order to measure moiré pattern.
As described above, there are several disadvantages that when measuring the three dimensional image by using the conventional moiré pattern, there is a shadow region, which is impossible to measure, at an arbitrary position of the measuring object, so that the three dimensional image of the measuring object can not be measured precisely.